A semiconductor memory device is a memory device which is fabricated using semiconductor materials, such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), and the like. Semiconductor memory devices are typically classified into volatile memory devices and nonvolatile memory devices.
The volatile memory devices may lose stored contents when they are powered off. The volatile memory devices may include, for example, a Static RAM (SRAM), a Dynamic RAM (DRAM), a Synchronous DRAM (SDRAM), etc. Nonvolatile memory devices, on the other hand, may retain stored contents even when powered off. The nonvolatile memory devices may include, for example, a Read Only Memory (ROM), a Programmable ROM (PROM), an Electrically Programmable ROM (EPROM), an Electrically Erasable and Programmable ROM (EEPROM), a flash memory device, a Phase-change RAM (PRAM), a Magnetic RAM (MRAM), a Resistive RAM (RRAM), a Ferroelectric RAM (FRAM), etc. The flash memory devices are divided into a NAND flash memory device and a NOR flash memory device.
Research on three-dimensional semiconductor memory devices is being performed to improve a degree of integration of semiconductor memory devices. A Three-dimensional semiconductor memory device has a different structure from that of a two-dimensional semiconductor memory device. For this reason, various methods for driving three-dimensional semiconductor memory devices are being researched.